Sequences were obtained for human (h) Survivin (Uniprot O15392), Bruce (Q9NR09), cIAP1 (Q13490), cIAP2 (Q13489), XIAP (P98170), ILP2 (Q96P09), MLIAP (Q96CA5), and NAIP (Q13075) with the individual BIR domains parsed. XIAP sequences for Drosophila (d, I6L9G1), Gallus (c, F6TJT0), Xenopus (x, A5D8Q0), Mus (m, Q60989), and Rattus (r, Q9R0I6) were additionally used. Sequence alignments were performed using Clustal Omega (Sievers et al., 2011 (link)) with default settings. A phylogenetic analysis of the domains was performed using maximum likelihood with the JTT matrix (Jones et al., 1992 (link)) and a consensus of 1000 bootstrap replicates (Felsenstein, 1985 (link)) using MEGA5 (Tamura et al., 2011 ). Initial tree for the heuristic search was obtained automatically by applying Neighbor-Join and BioNJ algorithms to a matrix of pairwise distances estimated using a JTT model, and then selecting the topology with superior log likelihood value. The analysis involved 31 amino acid sequences for 66 amino acids. Variants of XIAP associated with disease were identified in published literature, utilizing only single amino acid changes (including mutations to stop codons (X) and not mutations that result in a frameshift.